| Message ID | 20230517153812.2010174-1-anisse@astier.eu (mailing list archive) |
|---|---|
| State | Deferred, archived |
| Headers | show |
| Series | [v2] efivarfs: expose used and total size | expand |
On Wed, 17 May 2023 at 17:38, Anisse Astier <anisse@astier.eu> wrote: > > From: Anisse Astier <an.astier@criteo.com> > > When writing EFI variables, one might get errors with no other message > on why it fails. Being able to see how much is used by EFI variables > helps analyzing such issues. > > Since this is not a conventionnal filesystem, block size is > intentionnally set to 1 instead of PAGE_SIZE. > > x86 quirks of reserved size are taken into account; so that available > and free size can be different, further helping debugging space issues. > > With this patch, one can see the remaining space in EFI variable storage > via efivarfs, like this: > > $ df -h /sys/firmware/efi/efivars/ > Filesystem Size Used Avail Use% Mounted on > efivarfs 176K 106K 66K 62% /sys/firmware/efi/efivars > > Signed-off-by: Anisse Astier <an.astier@criteo.com> Thanks - I've queued this up now for v6.5 > --- > Notes: > > Patch isn't split per subsystem intentionally, for better understanding > of intent; I don't think it's necessary, but split could be trivial in > an another version. > > Changes since v1: > - update commit message to show how it can be used in userspace > - add comments to explain the values put in f_bsize, f_blocks, f_bfree > and f_bavail > - rebase on top v6.4-rc2 > > Thanks to Christan Brauner for the review. > > Regards, > > Anisse > > --- > arch/x86/platform/efi/quirks.c | 8 ++++++++ > drivers/firmware/efi/efi.c | 1 + > drivers/firmware/efi/vars.c | 12 ++++++++++++ > fs/efivarfs/super.c | 36 +++++++++++++++++++++++++++++++++- > include/linux/efi.h | 10 ++++++++++ > 5 files changed, 66 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c > index b0b848d6933a..587fa51230e2 100644 > --- a/arch/x86/platform/efi/quirks.c > +++ b/arch/x86/platform/efi/quirks.c > @@ -114,6 +114,14 @@ void efi_delete_dummy_variable(void) > EFI_VARIABLE_RUNTIME_ACCESS, 0, NULL); > } > > +u64 efi_reserved_space(void) > +{ > + if (efi_no_storage_paranoia) > + return 0; > + return EFI_MIN_RESERVE; > +} > +EXPORT_SYMBOL_GPL(efi_reserved_space); > + > /* > * In the nonblocking case we do not attempt to perform garbage > * collection if we do not have enough free space. Rather, we do the > diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c > index abeff7dc0b58..d0dfa007bffc 100644 > --- a/drivers/firmware/efi/efi.c > +++ b/drivers/firmware/efi/efi.c > @@ -211,6 +211,7 @@ static int generic_ops_register(void) > generic_ops.get_variable = efi.get_variable; > generic_ops.get_next_variable = efi.get_next_variable; > generic_ops.query_variable_store = efi_query_variable_store; > + generic_ops.query_variable_info = efi.query_variable_info; > > if (efi_rt_services_supported(EFI_RT_SUPPORTED_SET_VARIABLE)) { > generic_ops.set_variable = efi.set_variable; > diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c > index bfc5fa6aa47b..e9dc7116daf1 100644 > --- a/drivers/firmware/efi/vars.c > +++ b/drivers/firmware/efi/vars.c > @@ -245,3 +245,15 @@ efi_status_t efivar_set_variable(efi_char16_t *name, efi_guid_t *vendor, > return status; > } > EXPORT_SYMBOL_NS_GPL(efivar_set_variable, EFIVAR); > + > +efi_status_t efivar_query_variable_info(u32 attr, > + u64 *storage_space, > + u64 *remaining_space, > + u64 *max_variable_size) > +{ > + if (!__efivars->ops->query_variable_info) > + return EFI_UNSUPPORTED; > + return __efivars->ops->query_variable_info(attr, storage_space, > + remaining_space, max_variable_size); > +} > +EXPORT_SYMBOL_NS_GPL(efivar_query_variable_info, EFIVAR); > diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c > index 482d612b716b..c27de959cb5b 100644 > --- a/fs/efivarfs/super.c > +++ b/fs/efivarfs/super.c > @@ -13,6 +13,7 @@ > #include <linux/ucs2_string.h> > #include <linux/slab.h> > #include <linux/magic.h> > +#include <linux/statfs.h> > > #include "internal.h" > > @@ -23,8 +24,41 @@ static void efivarfs_evict_inode(struct inode *inode) > clear_inode(inode); > } > > +static int efivarfs_statfs(struct dentry *dentry, struct kstatfs *buf) > +{ > + u64 storage_space, remaining_space, max_variable_size; > + efi_status_t status; > + const u32 attr = (EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | > + EFI_VARIABLE_RUNTIME_ACCESS); > + > + buf->f_type = dentry->d_sb->s_magic; > + /* > + * This is not a normal filesystem, so no point in pretending it has a block > + * size; we declare f_bsize to 1, so that we can then report the exact value > + * sent by EFI QueryVariableInfo in f_blocks and f_bfree > + */ > + buf->f_bsize = 1; > + buf->f_namelen = NAME_MAX; > + > + status = efivar_query_variable_info(attr, &storage_space, &remaining_space, > + &max_variable_size); > + if (status != EFI_SUCCESS) > + return efi_status_to_err(status); > + buf->f_blocks = storage_space; > + buf->f_bfree = remaining_space; > + /* > + * In f_bavail we declare the free space that the kernel will allow writing > + * when the storage_paranoia x86 quirk is active. To use more, users > + * should boot the kernel with efi_no_storage_paranoia. > + */ > + if (remaining_space > efi_reserved_space()) > + buf->f_bavail = remaining_space - efi_reserved_space(); > + else > + buf->f_bavail = 0; > + return 0; > +} > static const struct super_operations efivarfs_ops = { > - .statfs = simple_statfs, > + .statfs = efivarfs_statfs, > .drop_inode = generic_delete_inode, > .evict_inode = efivarfs_evict_inode, > }; > diff --git a/include/linux/efi.h b/include/linux/efi.h > index 7aa62c92185f..d2b686191870 100644 > --- a/include/linux/efi.h > +++ b/include/linux/efi.h > @@ -703,6 +703,7 @@ static inline void efi_enter_virtual_mode (void) {} > extern efi_status_t efi_query_variable_store(u32 attributes, > unsigned long size, > bool nonblocking); > +extern u64 efi_reserved_space(void); > #else > > static inline efi_status_t efi_query_variable_store(u32 attributes, > @@ -711,6 +712,10 @@ static inline efi_status_t efi_query_variable_store(u32 attributes, > { > return EFI_SUCCESS; > } > +static inline u64 efi_reserved_space(void) > +{ > + return 0; > +} > #endif > extern void __iomem *efi_lookup_mapped_addr(u64 phys_addr); > > @@ -1042,6 +1047,7 @@ struct efivar_operations { > efi_set_variable_t *set_variable; > efi_set_variable_t *set_variable_nonblocking; > efi_query_variable_store_t *query_variable_store; > + efi_query_variable_info_t *query_variable_info; > }; > > struct efivars { > @@ -1087,6 +1093,10 @@ efi_status_t efivar_set_variable_locked(efi_char16_t *name, efi_guid_t *vendor, > efi_status_t efivar_set_variable(efi_char16_t *name, efi_guid_t *vendor, > u32 attr, unsigned long data_size, void *data); > > +efi_status_t efivar_query_variable_info(u32 attr, u64 *storage_space, > + u64 *remaining_space, > + u64 *max_variable_size); > + > #if IS_ENABLED(CONFIG_EFI_CAPSULE_LOADER) > extern bool efi_capsule_pending(int *reset_type); > > -- > 2.34.1 >
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c index b0b848d6933a..587fa51230e2 100644 --- a/arch/x86/platform/efi/quirks.c +++ b/arch/x86/platform/efi/quirks.c @@ -114,6 +114,14 @@ void efi_delete_dummy_variable(void) EFI_VARIABLE_RUNTIME_ACCESS, 0, NULL); } +u64 efi_reserved_space(void) +{ + if (efi_no_storage_paranoia) + return 0; + return EFI_MIN_RESERVE; +} +EXPORT_SYMBOL_GPL(efi_reserved_space); + /* * In the nonblocking case we do not attempt to perform garbage * collection if we do not have enough free space. Rather, we do the diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index abeff7dc0b58..d0dfa007bffc 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -211,6 +211,7 @@ static int generic_ops_register(void) generic_ops.get_variable = efi.get_variable; generic_ops.get_next_variable = efi.get_next_variable; generic_ops.query_variable_store = efi_query_variable_store; + generic_ops.query_variable_info = efi.query_variable_info; if (efi_rt_services_supported(EFI_RT_SUPPORTED_SET_VARIABLE)) { generic_ops.set_variable = efi.set_variable; diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c index bfc5fa6aa47b..e9dc7116daf1 100644 --- a/drivers/firmware/efi/vars.c +++ b/drivers/firmware/efi/vars.c @@ -245,3 +245,15 @@ efi_status_t efivar_set_variable(efi_char16_t *name, efi_guid_t *vendor, return status; } EXPORT_SYMBOL_NS_GPL(efivar_set_variable, EFIVAR); + +efi_status_t efivar_query_variable_info(u32 attr, + u64 *storage_space, + u64 *remaining_space, + u64 *max_variable_size) +{ + if (!__efivars->ops->query_variable_info) + return EFI_UNSUPPORTED; + return __efivars->ops->query_variable_info(attr, storage_space, + remaining_space, max_variable_size); +} +EXPORT_SYMBOL_NS_GPL(efivar_query_variable_info, EFIVAR); diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c index 482d612b716b..c27de959cb5b 100644 --- a/fs/efivarfs/super.c +++ b/fs/efivarfs/super.c @@ -13,6 +13,7 @@ #include <linux/ucs2_string.h> #include <linux/slab.h> #include <linux/magic.h> +#include <linux/statfs.h> #include "internal.h" @@ -23,8 +24,41 @@ static void efivarfs_evict_inode(struct inode *inode) clear_inode(inode); } +static int efivarfs_statfs(struct dentry *dentry, struct kstatfs *buf) +{ + u64 storage_space, remaining_space, max_variable_size; + efi_status_t status; + const u32 attr = (EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | + EFI_VARIABLE_RUNTIME_ACCESS); + + buf->f_type = dentry->d_sb->s_magic; + /* + * This is not a normal filesystem, so no point in pretending it has a block + * size; we declare f_bsize to 1, so that we can then report the exact value + * sent by EFI QueryVariableInfo in f_blocks and f_bfree + */ + buf->f_bsize = 1; + buf->f_namelen = NAME_MAX; + + status = efivar_query_variable_info(attr, &storage_space, &remaining_space, + &max_variable_size); + if (status != EFI_SUCCESS) + return efi_status_to_err(status); + buf->f_blocks = storage_space; + buf->f_bfree = remaining_space; + /* + * In f_bavail we declare the free space that the kernel will allow writing + * when the storage_paranoia x86 quirk is active. To use more, users + * should boot the kernel with efi_no_storage_paranoia. + */ + if (remaining_space > efi_reserved_space()) + buf->f_bavail = remaining_space - efi_reserved_space(); + else + buf->f_bavail = 0; + return 0; +} static const struct super_operations efivarfs_ops = { - .statfs = simple_statfs, + .statfs = efivarfs_statfs, .drop_inode = generic_delete_inode, .evict_inode = efivarfs_evict_inode, }; diff --git a/include/linux/efi.h b/include/linux/efi.h index 7aa62c92185f..d2b686191870 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -703,6 +703,7 @@ static inline void efi_enter_virtual_mode (void) {} extern efi_status_t efi_query_variable_store(u32 attributes, unsigned long size, bool nonblocking); +extern u64 efi_reserved_space(void); #else static inline efi_status_t efi_query_variable_store(u32 attributes, @@ -711,6 +712,10 @@ static inline efi_status_t efi_query_variable_store(u32 attributes, { return EFI_SUCCESS; } +static inline u64 efi_reserved_space(void) +{ + return 0; +} #endif extern void __iomem *efi_lookup_mapped_addr(u64 phys_addr); @@ -1042,6 +1047,7 @@ struct efivar_operations { efi_set_variable_t *set_variable; efi_set_variable_t *set_variable_nonblocking; efi_query_variable_store_t *query_variable_store; + efi_query_variable_info_t *query_variable_info; }; struct efivars { @@ -1087,6 +1093,10 @@ efi_status_t efivar_set_variable_locked(efi_char16_t *name, efi_guid_t *vendor, efi_status_t efivar_set_variable(efi_char16_t *name, efi_guid_t *vendor, u32 attr, unsigned long data_size, void *data); +efi_status_t efivar_query_variable_info(u32 attr, u64 *storage_space, + u64 *remaining_space, + u64 *max_variable_size); + #if IS_ENABLED(CONFIG_EFI_CAPSULE_LOADER) extern bool efi_capsule_pending(int *reset_type);